In the operation of a carding machine, non-fibrous contaminants are normally removed from the cotton fibers by passing the fibers about a rotating lickerin cylinder which rotates in close proximity to mote knives, grid bars, or perforated plates. More recently, as illustrated in U.S. Pat. Nos. 3,205,538 to Miller, et al and 3,537,144 to King, Jr., it has been discovered that the trash can be separated from the fibers by exposing a transverse portion equal to approximately one-eighth of the total peripheral surface of the lickerin cylinder instead of using grid bars or mote knives; the forward and rear edges of the exposed area having downwardly extending partitions which extend across the width of the lickerin cylinder. Such an exposed area permits sufficient time for fibers and trash to react to aerodynamic and centrifugal forces thus accomplishing separation of the trash.
When utilizing an apparatus of the foregoing type, the trash and short fibers discharged from the lickerin cylinder are discharged onto the floor or into the area below the carding machine resulting in undesirable working conditions. Furthermore, the reusable fiber that is present in the discharged material becomes excessively contaminated, resulting in difficulty in processing the fiber for subsequent use.
Desirably, the trash and short fiber should be conveyed away from the area beneath the lickerin cylinder as it is there deposited to an area remote from the carding machine. Attempts to do so, however, as by merely connecting a vacuum conveyant system to prior art apparatus results in withdrawal of an excessive amount of fiber from the lickerin cylinder due to the resultant suction on the surface of the lickerin itself.